Bitcoin Habrahabr

Click here for cryptocurrency Links

Banking or Other Fees to Use Bitcoins
There are small fees to use bitcoins, which are paid to three groups of bitcoin services:

Servers (nodes) that support the network of miners
Online exchanges that convert bitcoins into dollars
Mining pools
The owners of some server nodes charge one-time transaction fees of a few cents every time money is sent across their nodes, and online exchanges similarly charge when bitcoins are cashed in for dollars or euros. Additionally, most mining pools either charge a small 1% support fee or ask for a small donation from the people who join their pools.

While there are nominal costs to use bitcoin, the transaction fees and mining pool donations are cheaper than conventional banking or wire transfer fees.

Bitcoin Production Facts
Bitcoin mining involves commanding a home computer to work around the clock to solve proof-of-work problems (computationally intensive math problems). Each bitcoin math problem has a set of possible 64-digit solutions. A desktop computer, if it works nonstop, might be able to solve one bitcoin problem in two to three days, however, it might take longer.

Computer creating bitcoin
Caiaimage/Adam Gault / Getty Images
A single personal computer that mines bitcoins may earn 50 cents to 75 cents per day, minus electricity costs. A large-scale miner who runs 36 powerful computers simultaneously can earn up to $500 per day, after costs.

A small-scale miner with a single consumer-grade computer may spend more on electricity than they will earn mining bitcoins. Bitcoin mining is profitable only for those who run multiple computers with high-performance video processing cards and who join a group of miners to combine hardware power.

This prohibitive hardware requirement is one of the biggest security measures that deter people from trying to manipulate the bitcoin system.

Bitcoin Security
People who take reasonable precautions are safe from having their personal bitcoin caches stolen by hackers.

There are two main security vulnerabilities when it comes to bitcoin:

A stolen or hacked password of the online cloud bitcoin account (such as Coinbase)
The loss, theft, or destruction of the hard drive where the bitcoins are stored
More than hacker intrusion, the real loss risk with bitcoin revolves around not backing up a wallet with a fail-safe copy. There is an important .dat file that is updated every time bitcoins are received or sent, so this .dat file should be copied and stored as a duplicate backup every day.

The public collapse of the Mt. Gox bitcoin exchange service was not due to any weakness in the bitcoin system. Rather, the organization collapsed because of mismanagement and the company's unwillingness to invest in appropriate security measures. Mt. Gox had a large bank with no security guards.

***** of Bitcoins
There are three known ways that bitcoin currency can be *****d:

TECHNICAL WEAKNESS: TIME DELAY IN CONFIRMATION
Bitcoins can be double-spent in some rare instances during the confirmation interval. Because bitcoins travel peer-to-peer, it takes several seconds for a transaction to be confirmed across the P2P computers. During these few seconds, a dishonest person who employs fast clicking can submit a second payment of the same bitcoins to a different recipient.

While the system eventually catches the double-spending and negates the dishonest second transaction, if the second recipient transfers goods to the dishonest buyer before receiving confirmation of the dishonest transaction, then the second recipient loses the payment and the goods.

HUMAN DISHONESTY: POOL ORGANIZERS TAKING UNFAIR SHARE SLICES
Because bitcoin mining is best achieved through pooling (joining a group of thousands of other miners), the organizers of each pool choose how to divide bitcoins that are discovered. Bitcoin mining pool organizers can dishonestly take more bitcoin mining shares for themselves.

HUMAN MISMANAGEMENT: ONLINE EXCHANGES
With Mt. Gox as the biggest example, the people running unregulated online exchanges that trade cash for bitcoins can be dishonest or incompetent. This is similar to Fannie Mae and Freddie Mac investment banks going under because of human dishonesty and incompetence. The only difference is that conventional banking losses are partially insured for the bank users, while bitcoin exchanges have no insurance coverage for users.

Three Reasons Why Bitcoins Are Such a Big Deal
There is a lot of controversy around bitcoins.

NOT CREATED BY A CENTRAL BANK OR REGULATED BY ANY GOVERNMENT
Banks don't log money movement, and government tax agencies and police cannot track the money. This may change, as unregulated money is a threat to government control, taxation, and policing. Bitcoins have become a tool for contraband trade and money laundering because of the lack of government oversight. The value of bitcoins skyrocketed in the past because wealthy criminals purchased bitcoins in large volumes. Because there is no regulation, people can lose out as a miner or investor.

BITCOINS COMPLETELY BYPASS BANKS
Bitcoins are transferred through a peer-to-peer network between individuals, with no middleman bank to take a slice. Bitcoin wallets cannot be seized or frozen or audited by banks and law enforcement. Bitcoin wallets cannot have spending and withdrawal limits imposed on them. Nobody but the owner of the bitcoin wallet decides how the wealth is managed.

BITCOIN TRANSACTIONS ARE IRREVERSIBLE
Conventional payment methods such as a credit card charge, bank draft, personal check, or wire transfer benefit from being insured and reversible by the banks involved. In the case of bitcoins, every time bitcoins change hands and change wallets, the result is final. Simultaneously, there is no insurance protection for a bitcoin wallet. If a wallet's hard drive data or the wallet password is lost, the wallet's contents are gone forever.